Bug 196065 - External display pixelated after upgrade to kernel >= 4.11.0-rc1
Summary: External display pixelated after upgrade to kernel >= 4.11.0-rc1
Status: RESOLVED INVALID
Alias: None
Product: Drivers
Classification: Unclassified
Component: Console/Framebuffers (show other bugs)
Hardware: Intel Linux
: P1 normal
Assignee: James Simmons
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-06-14 02:27 UTC by Neil Kownacki
Modified: 2017-06-28 13:12 UTC (History)
0 users

See Also:
Kernel Version: 4.11.0-rc1
Subsystem:
Regression: Yes
Bisected commit-id:


Attachments
dmesg, inxi, Xorg.0.log, fb0 sysfs, EDID (260.00 KB, application/x-tar)
2017-06-14 02:27 UTC, Neil Kownacki
Details
Fedora default config for 4.11.3 and config used for drm-tip 4.12.0-rc4 (53.12 KB, application/x-bzip)
2017-06-15 02:08 UTC, Neil Kownacki
Details

Description Neil Kownacki 2017-06-14 02:27:32 UTC
Created attachment 256993 [details]
dmesg, inxi, Xorg.0.log, fb0 sysfs, EDID

I have a Thinkpad X270 with HDMI out and Intel HD Graphics 620, running Fedora 25, Mint, and Xubuntu.  I had been using a 26" Vizio E261VA TV as an external monitor for a few months without any issues, but after upgrading to any kernel >= 4.11.0-rc1, the display becomes very pixelated and text is almost unreadable.  On 4.10 it looks fine.  I did some research, and one thing I noticed was that the "mode" for the fb0 device is now set to "U:1360x768p-0".  In the working kernel it's "U:1920x1080p-0" (see attachment.)

The native resolution for this TV is 1360x768, which is the resolution I run it at, and the laptop screen is running at 1920x1080.  I have tried uninstalling xorg-x11-drv-intel (attached logs are using the modesetting driver) but it didn't make a difference.  I have also tried booting the kernel with the parameter video=HDMI-A-2:1920x1080M@60.  That will change the framebuffer mode back to what it was in 4.10, but I still can't seem to get the pixelation to go away.

I noticed quite a few changes in the logs for 4.11.0-rc1 involving drm/i915, framebuffers, EDID, and HDMI, so I assume this has something to do with that.  I'm not 100% sure it involves the framebuffer per se, but the resolution change caught my eye.  I see the pixelation before X even starts, while the startup checks are running down the screen.

Hopefully this is enough info.  Let me know if you need anything else.  Thanks!
Comment 1 Neil Kownacki 2017-06-15 02:08:01 UTC
Created attachment 257007 [details]
Fedora default config for 4.11.3 and config used for drm-tip 4.12.0-rc4

I should add that I built a kernel from cgit.freedesktop.org/drm-tip today and I still see the issue.  I unfortunately don't have the configs from the 4.10 and 4.11 kernels that I ran to get the initial logs, but I can redo if necessary.  Attached the Fedora config for 4.11.3 and the config I used for building the drm-tip kernel.
Comment 2 Jani Nikula 2017-06-28 13:12:24 UTC
Please file drm/i915 bugs at https://bugs.freedesktop.org/enter_bug.cgi?product=DRI&component=DRM/Intel

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